Alternate
U S Highways: Bannered Routes

Bannered US routes have been
in wide use since the early 1930's. Some of the earliest examples
I have seen are the US 27A's in central Michigan in 1932. A 1932
AASHO policy statement allowed for cities to erect
"Alternate" routes within a city, as long as these
routes reconnected with the main route, without AASHO approval.
The next year AASHO attempt to regain control of these short
system additions, but the states where such routes had been
adopted had established a precedent. Many states still consider
it none of AASHTO's business if small, local additions to the US
route system are posted. These banners have also been seen in the
use of an alphabetical-based suffix system, decreasing in
importance as the letters progressed: A for for the longer main
rooute following Alternate; B for a Bypass around a city center;
C for City traffic into the heart of downtown and T for
Temporary. Temp US Routes have been suffixed "T" since
the 1920's. The suffix B is also used for Business routes by many
states now. Y has been seen used for Spur routes. Some states use
suffixes as branches and loops off a mainline route, like NY 11B
off of US 11. This would be Alt US 11 in many other states, and
is not a Business or Bypass route. The primary source for this
site was U.S. Numbered Highways - 1989 edition published by
AASHTO. Additional information has been gathered from old road
atlases and maps, information E-mailed to me, various websites posted by
other people, and personal observations. The historical routes
for these pages are still being updated, and will be for the
forseeable future. Current routes are complete per AASHTO data,
and not field verified. Assistance is welcomed and encouraged.